However, it doesn't always get its predictions right - ask George Osborne, the Chancellor.

Last year the Fund warned him his austerity programme was 'playing with fire' only to make an embarrassing about-turn earlier this year as it predicted the UK would be the fastest growing economy in the G7 in 2014.

So what's the verdict on the pound according to the Economist's Big Mac Index?

The index - which the Economist stresses is a lighthearted guide - compares the cost of a Big Mac burger in different countries to assess whether currencies are at their correct level.

It puts the cost of a Big Mac in Britain at £2.89, compared to £2.81 in the US and £2.91 in the eurozone.

This suggests the pound is 2.6pc overvalued against the dollar and 0.6pc undervalued against the euro, according to the index.

It implies an exchange rate for the pound of 1.66 against the dollar and 1.27 against the euro, which compared with the $1.6938 and €1.2629 sterling was trading at on Tuesday.

So who's do you think is the better barometer of exchange rates: the more digestible Burgernomics or the serious IMF?

• This is how the Economist explains its index: Burgernomics was never intended as a precise gauge of currency misalignment, merely a tool to make exchange-rate theory more digestible. Yet the Big Mac index has become a global standard, included in several economic textbooks and the subject of at least 20 academic studies.

The Telegraph Investor

Editor's comment:

Priced to be great value for new investors and those with large portfolios.